Speed control



July 2,1929. c.-R. ALDEN SPEED CONTROL Filed Dec. 4, 1925 mm 8 M Q I d KM fiaduwoew Patented July 2, 1929.

ITED STATES PATENT OFFICE.

CARROLL lEt. ALDEN, OF DETROIT, MICHIGAN, ASSIGNOR TO EX-OELL-O TOOL & MANU- FAC'IURING 00., A CORPORATION OF MICHIGAN.

SPEED CONTROL.

Application filed December a, 1925. Serial No. 73,165.

This invention relates to a speed control tor rotary tools which are subject to speed slaclrening loads when in use. The invention 1s partlcularly adapted for fluid driven turbine motors and particularly for motors ofa class used for driving small high speed rotary tools,

such as grinding wheels. Y

For example, an air driven turbine wheel may be used to drive a grinding wheel spindle, such a motor being used when the grinding wheel is of a small size requiringlittle power but great speed. Such a wheel is used in internal grinding of very small holes and for many other grinding operations. When idling the wheel will be revolved at a suitable high speed by the air motor, but when in contact with work there will be slackening of speed depending upon the amount of feed or the character of the work. The speed variation ot such a wheel is troublesome and undesirable in that no uniform action can be obtained from the wheel. Sometimes in order to obtain a certain cutting speed for the tool the fluid supplied to the motor under load is excessive for the idling rotation of the wheel, thus causing the motor and the wheel to run at a dangerous speed unless controlled. To overcome these conditions a manual adjustment of the fluid supply is necessary.

The present invention aims to provide an automatic speed control for such tools.

Une object of the invention is to'provide an electrically, operated control for the power supply to maintain a substantially constant speed of the tool.

A. further object is to provide an auxiliary power supply having such a control. p

A still further object is to provide an auxiliary speed-controlled driving force for the spindle in addition to the normal driving force.

1n the accompanying drawings the invention is illustrated as embodied in an air driven turbine motor for driving verysmall grinding elements similar to that shown.

In the drawings, Figure 1 is an air driven motor showing a portion ofthe rotor region in cross section, the fluid-supply system including a solenoid valve in cross section, a speed governor, and electrical circuits.

Fig. 2 shows a plan view of the speed governor of Figure 1 viewed in elevation from the line 22 of Figure 1.

' for admitting fluid from the compartment 13 valve .17.

Fig. 3 shows a modified form of the invention including modifications in the motor, the governor, and the fluid supply system.

It will, of Course, be understood that the ap plication of the invention is not limited to the present disclosure nor is the invention to be construed as limited by the construction illustrated in the drawings. To those skilled in the art, it will appear that the invention is sub JeQ-t to various changes and modifications of the arrangements illustrated in the drawings, and hereinafter described in detail, the true nature and scope of the invention being expressed in the appended claims.

Tn the drawings 5 illustrates a casing or housing of an air driven motor. The housing encloses a spindle 6 which carries at its ton ward end a work tool, in the present instance this being a grinding tool 7 suitably mounted for rotation with the spindle. The rear end of the housing 5 has a turbine rotor 8 rigid on the spindle 6. In the present instance the rotor 8 has spiral blades 9 thereon which receive driving fluid directed substantially axially of the spindle. The fluid strikes the rotor from the rear of the casing, passes therethrough and is exhausted at the forward end in the region designated 10. A substantially annular fluid passage 11 is provided along the length of the housing so that the driving air cools the spindle bearings. 'A fixed plate 12 is located adjacent the rotor 8 separating it from a fluid pressure compartment 13. A suitable nozzleistructure is provided in the plate, this comprising in the present instanceone or more nozzle holes 14:

onto the rotor blades 9. A source of fluid supply represented by pipe 15 is connected by a pipe line 16 to the compartment 13, and a regulating shut-off valve 17 is placed in this line. The apparatus so far described represents the basic device upon which the speed control of the invention is applied. lit is obvious that no control of motor speed can be obtained Without some control of the In order to furnish a control a speed governor is attached to the motor. This is preferably provided on a rearward extension 18 of the spindle6. The governor may be of any preferred form and in thepresent instance it is arranged to open an electric switch on attaininga certain desired speed. The type of governor preferably employed is particularly adapted for high speed spindles because of its smooth and balanced action and because Of the absence of mechanical joints and connections.

The governor shown in the drawings com-.

prises a magnetic disc 19 having north and south poles as indicated. Adjacent this disc is a movable metallic member dragged by the magnetic force. It consists preferably of a surrounding metallic cup 20 rotatably mountedon an axis coincident with the axis of the disc. A finger or plate 21 rigid with the cup bears an electrical contact 22. A second and fixed electric contact 23 is carried on a part 24 rigid with the machine unit. A spring 25 between the parts 24 and the cup 20 is provided as a means forcing the two contacts into closed, position to close an electric circuit between wires 26 and 27 connected to the contacts. The wire 26 is connected to one terminal 28 of a source of electric power, whereas the other wire 27 is connected to the other terminal 29 of such source through suit- I able means operable to control the fluid sup ply. The rotation of the magnetized disc '19 drags the cup 20 with it against the action of,

the spring 25 and at a definite speed breaks the contact.

. In Figure 1 the motor is shown having two fluid compartments, compartment 13 already described, and a second compartment 30 separated from the compartment 13 by a partition .31 which is part of the casing. One or more nozzle holes 32 similar to the holes 14 are provided in the plate 12 on the side of the center opposite the holes 14. A fluid line 33 connects compartment 30 and the primary fluid pressure source 15. In the line 33 there is an electrically controlledfluid regulating means such as the solenoid valv,e 34. This valve comprises a casing 35 having a valve seat 36 and a valve head 37 which is herein shown as normally held seated by the fluid pressure of the line. The valve head 37 is carried by a magnet core 38, the whole .forming a rigid structure which is housed within a tight casing 39 of which the valve casing 35 4 is a part. A solenoid coil 30 surrounds the I part of the casing 39 which houses the core 38.

A relay device 41 is preferably interposed between the solenoid valve and the circuit of wires 26 and 27, the current for operating the solenoid passing from the terminal 28 through .wire 42, solenoid 40, wire 43, relay switch 44 and wire 45, to the other terminal 29. The relay magnet 46 is placed in series with wires 27 and 45.

The device above described is subject to two modes of operation, the first of which uses but oneline of fluid supply to the motor. First'assume the valve 17 to be tightly closed so-that the fluid line 16 may be disregardedjin the first mode of operation. Thegovernor, switch contacts 22 and 23 willbe closed below a certain speed of the motor.

ting the solenoid valve to close. The speed;

will thus be reduced which will again cause the valve to open. lVhen operated in this manner the solenoid valve will flutter to maintain the speed substantially near the speed setting of the governor. For this reason the relay operation is desirable as the solenoid takes considerable current which one would not wisely pass through the governor contacts.

The second operationof the device of Figure 1 is the preferable one. It differs only from the first mode of operation in that the valve 17 is opened a suflieient amount to main tain a driving force on the spindle when the solenoid valve is shut. The idling valve 17 is preferably set to maintain the wheel idly rotated at a desired speed which is preferably just above the speed at which. the governor operates. The application of a load to the wheel suflicient to reduce the speed will cause the. solenoid valve 34 to open and to permit the supply of an auxiliary driving force on the rotor thereby causing it to increase in speed. This auxiliary line is then operated under speed control for the purpose of maintaining a constant speed. When the primary supply 15 is'the only power source the idling structure are involved. First, a different type ofispeed governor and switch is employed. The main spindle of the motor is provided with a larger rear extension shaft 50 having a fly-ball governor. The extension shaft 50 has a well51 formed in the end thereof, which well is screw-threaded at its opening to receive an adjusting nut 52, through which passes a plunger 53having a head 54 within the well. A spring 55 is compressed between the nut 52 and the plunger head 54. Two or more fly balls 56 carried on a bell-crank stem 57 are pinned at 58 intn the shaft 50. The free ends 59 of the stems are arranged to press on the plunger head as the increased speed moves the balls outwardly. A simple switch designated generally as 60 is operated by the plunger to open at a predetermined speed depending, u on the adjustment of the nut 52. The switch 60 and a v Fig. 3 these supply lines are designated 63 and 6A, the lines 63 having an idllng valve ot the regulating shut-ofl type. A single primary fluid pressure source is designated as 66. The lines 61 and 62 unite beyond their valves and the suppliesot both lines are caused toact together upon the motor through a single line 67. It is obvious that this is not essentially diflerent from the arrangement in Figure 1. However, in order to efl'ect speed control, the volume relation of the valves 61 and 65 and the pressure fluid source 66 must be such that the opening of the auxiliary supply 64 at the solenoid valve reflects a substantial increase in driving fluid or driving force over what normally passes throu h the idling valve 65.

The third modification of Fig. 3 concerns the motor construction. The use of but one fluid supply line 67 to the motor does not require two supply compartments adjacent the rotor, consequently but one compartment 68 is employed with only one set of nozzle holes 69 in plate 70 which corresponds to theplate 12 in Figure l.-

lln the above described embodiments of the invention air is contemplated as the driving fluid butit is to be understood that a liquid fluid supply is equally within the scope of the invention when embodied in fluid motors.

ll claim as my invention:

1. For a high speed turbine-driven rotary cutter adapted to receive intermittent working loads, a speed-controlled motor comprising, incombination, a casing, a tool carrying spindle therein, a rotor on said spindle, two lnde endent ozzle structures for said rotor, a uid supply connected to one nozzle structure for effecting an idling speed of the tool above apredetermined speed, an auxiliary fluid supply connected to the second nozzle structure, means to cut oil said. auxiliary supply, a speed governor operated by the motor to cause said,supply to be opened below said-predetermined speed, and operating means .actuated by the" governor to effect operation. of the cut-ofl means, where byanexcessive speed-slackening load on the tool causes the governor to open the auxiliary fluid supply to maintain the predetermined speed of the tool. i

2. For a high speed turbine-driven rotary cutter adapted to receive intermittent Working loads, a speed-controlled motor comprising, incombination, a casing, a tool-carrying spindletherein, a rotor on said spindle, two inde endent nozzle structures for said rotor, a uid supply' connected to one nozzle structure for eflecting an idling speed of the, tool above a predetermined'speed, an aux iliary fluid supply line connected to the sec ond nozzle structure, a solenoid valve in said auxiliary supply line, an electric switch arranged to cause said solenoid valve to open and close, a spcedgovenor operated by the niotor to open and close said switch at said predetermined speed during an excessive speed-slackening load on said tool, whereby to maintain said predetermined s eed.

3. For a high speed turbineriven tool adapted to receive intermittent working loads, a speed controlled motor comprising, in combination, a casing, a tool-carrying spindle therein, two independent means for supplying driving fluid to said spindle, afluid supply for each means, one of said supplies being suficient to maintain the tool above a predetermined speed in the idlerotation of the tool, the other supply being an auxiliary supply eflective when" an excessive speedslackening load is applied to the tool, a speed governor operated by the motor, and means operated by the governor to cut in and out said auxiliary supply,

A. A speed-controlled fluid-operated motor comprisinggin combination, a motor casing, fluid driven rotor means thereln, two ll'ldfi'.

pendent nozzle structures for said rotor means, a fluid supply line for each nozzle structure, a regulator in one line adapted to permit said rotor to be driven at a predetermined idling speed, an electrically operated cut-out means in the second line a speed gov ernor operated by the motor, and a switch operated by the governor at a predetermined speed, said switch being arranged to actuate said electrically operated cut-out means. v

5. A speed-controlled fluid-operated motor comprising, in combination, a motor casing, a fluid driven rotor therein, two independent nozzle structures tor said rotor, a fluid supply line for each nozzle structure, a regulator in one line adapted to permit said rotor to be driven at a predetermined Lidling speed, means to cut-ofl' the supply of fluid to the sec- 0nd line, a speed governor operated by the motor, and-means operated by the governor at a predetermined speed to effect operation of the cutting-ofi' means of the second line.

6. A speed-controlled fluid-operated motor comprising, in combination, a motor casing, fluid driven rotor means therein, two independent nozzle structures for said rotor means, a fluid supply line for each nozzle structure, a primary source of fluid supply, separate lines connecting said source to each nozzle structure, a regulating valve in one line, a cut-off valve in the other line adapted to permit said rotor to be driven at a predetermined idling speed, a speed governor operated by the motor, and means actuated by the speed governor to open and close said shut-off valve at a predetermined speed.

For a high speed motor-driven rotary todl adapted to receive speed-slackening loads, a speed-controlled driving means comprising, in combination, a motor for the tool, power means for the motor arranged to drive the tool above a predetermined speed in the idle rotation oflthe tool, a speed governor op: erated' by the motor, an auxiliary source of power arranged to be connected for driving the motor upon aslackening ofspeed below said predetermined speed, and means actuated by the governor to cut in and out the auxiliary source of power.

8. A speed control for a fluid-driven tur-. bine motor comprising, in combination, a fluid supply line for said motor, a solenoid valve in said line to turn on or off the fluid supply, an electric switch, a circuit containing said switch arranged to open and close the valve, a speed governor operated by the motor and arranged to close said switch below a given speed of the motor and to open said switch above said predetermined speed, whereby an excessive speed of-the motor is prevented by the cutting'ofi action of said valve and other means to su ply fluid to the motor when the valved supp y is out 011'.

9. A speed control for a fluid-driven turbine motor comprising, in combination, a fluid supply line-for running the motor, an electrically operated valve insaid'line, an

electric switch a circuit containing said switch arranged to open andclose said valve, aspeed governor operated by the motor to open and close said switch at a predetermined speed, whereby an excessive speed of the motor operates through said switch to cut off the valved fluid supply, and other means to supply fluid to the motor for driving said motor at a predetermined idling speed when the valved supply is cut off.

10. A'speed control-for a fluid-driven turblne .rnotor compri in combination, a fluid fsifa-pply line for "running the motor, a valve open and close the fluid line, eleetrical means-to operate the valve including an electric switch, a speed governor operated by the motor to 0 en and close said switch at a predetermine speed of the motor, and other means to supply driving fluid to the motor'to' operate said motor at a predetermined idling speed when said valve is closed.

11. A speed cont-r01 for a fluid-driven turbine motor comprising, in combination, a. fluid supply line for running the motor, a

valve to open and close the fluid line, electrical means to operate the valve including an electric switch, a speed governor operated by the motor to open and close said switch at a predetermined speed of the motor, another fluid line to run the motor and a regulating valve in said other line to permit said motdir to be driven at a predetermined idling spec 12. A speed control for a fluid-driven turbine motor comprising, in combination, a source of fluid supply for the motor, electrically operated means to cut-off said supply including an electric switch, a speed governor operated by the motor to open and close said switch at a predetermined speed of the motor, a second source of fluid supply ada ted to supply the motor continuously with riving fluid and effective when the first supply is cut off to keep the motor running a ove the predetermined speed in the idle rotation of the motor. I

13. A speed control for a fluid-driven turbine motor comprising, in combination, a source of fluid supply for the motor, means to cut off said supply, a speed governor operated by said motor to cause said means to cut in or out said fluid supply at a predetermined speed, and a second source of fluid arranged to supply driving fluid continuously to the motor and effective when the first supply is cut off to keep the motor running above the predetermined speed in the idle rotation of the motor. J

14. In combination, a rotary spindle. having thereon a high speed fluid turbine driven rotor adapted at one end to receive a small rotary tool, a magnetized disk at the other end of the spindle rigid and concentric therewith, a rotary element adjacent said disk adapted to be dragged by the rotating magnetized disk, a spring positioned to oppose the dragging action, an electric switch associated with the dragged element, said switch being arranged to be operated at a predetermined speed, and a fluid supplying system for the rotor controlled by the electric switch.

15. In combination, a rotary spindle having thereon a'high speed fluid turbine-driven rotor, said spindle being adapted at one end to receive asmall rotary tool, a disk at the other end of said spindle rigid and concentric therewith, a rotatable element alined with said disk and concentric therewith, one of said alinedl parts being magnetized and closely associated with the other to exert a dragging action between them, means to resist the dragging action, an electric switch associated with the dragged element arranged to be operated at a predetermined speed, and a fluid supply system for the rotor controlled by the electric switch.

16. In combination, a single rotary spindle having thereon a high speed fluid turbinedriven rotor, said spindle being adapted at ging action on the other one, means to resist motionof said element resulting from said dragging action, an electric switch associated with the dragged element arranged to be operated at predetermined speed, and a fluid supply system for the rotor controlled by the electric switch.

17. In combination, a spindle having thereon a high speed fluid turbine-driven rotor and adapted at one end to receive a small ro tary tool, a metallic disk rotatablewith said spindle, a movable element closely associated with said disk, one of said associated parts being 1nagnetize@ to exert a dragging force between them to move the element by rotation of the disk, means to resist said motion, an electric switch associated with the moved element to be operated at a predetermined speed of the disk, and a fluid supply system for the rotor controlled by said switch.

18. A speed control for a fluid driven turbine motor comprising, in combination, means to supply pressure fluidito operate the motor at a predetermined speed when idling, an auxiliary fluid supply l1ne for operating the motor at a predetermined speed under varying loads, and means to control said auxiliary fluid supply line, said means comprising a solenoid valve controlling the passage of fluid thru said line and arranged when deenergized normally to shut off said fluid supply, and a speed governor operated by the motor arranged to energize said solenoid to open said valve at said second mentioned predetermined speed of the motor.

19. A speed control for a fluid driven turbine motor comprising, in combination, a fluid supply line for running the motor at a constant predetermined idling speed, an auxiliary fluid supply line for maintaining the speed of the motor under load, a solenoid valve in said auxiliary line for controlling the passage of fluid theret-hrough, said valve being arranged to completely shut off the fluid supply when deencrgized and to be completely open when energized, and a speed governor operated by said motor adapted to maintain said predetermined speed of said motor under load by energizing and deenergizing said solenoid to produce a fluttering action thereof at that speed.

In testimony whereof, I have hereunto atfixed my signature.

CARROLL R. ALDEN.

CERTIFICATE OF CORRECTION.

Patent N5. 1. 718,935.

Granted July 2, 1 929, to

CARROLL R. ALDEN.

it is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page'4, lines 5 to 7, claim 6, strike out the words "adapted to permit said rotor to be driven at a predetermined idling speed" and insert the same to follow after the word "line"- first occurrence, line 5 of same claim; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Oiliice.

Signed and sealed this 13th day of August, 1929.

(Seal) M. J. Moore, Acting Commissioner of Patents. 

